...ぬ => Not (Negative) N3
Emphasize negative meaning
のを知っていますか => Do you know...? N4
ねばならない/ねばならぬ/ねば => have to do; must; should ~ N2
~ぬうちに => While not....; before... N1
Time
ぬきにして/~ぬきで => Exclude A; Stop/end A; Without A N2
Miscellaneous
~ぬばかり => As if; as though N1
Situation
~ぬまに => without one's knowledge, without noticing N1
Time
かも[知「し」]れない => Might A, maybe A, perhaps A N3
Sentence Endings
ぬく => Do A until the end/last N2
Will, Decision, “Doing”
ぬまでも => not to say; although it does not reach the level of ~ N1
Description
~とも~ともつかぬ/ともつかない      => whether A or B (shows doubt or uncertainty between the two things) N1
くらいなら/ぐらいなら => rather than (do …)​ N1